About 40 percent of the public water supply for the City of Huntsville, Alabama, is withdrawn from the Tennessee River. The watershed and presumed source area for the Tennessee River at the Huntsville intake (river mile 340) encompasses a 25,000-square-mile area which is predominantly (about 60 percent) forested land. Numerous impoundments along the Tennessee River upstream from the Huntsville intake regulate streamflow and water quality in the river, thus dampening short-term fluctuations caused by runoff. During storms, however, the quality of water at the intake is greatly affected by the smaller (570 square miles), predominantly agricultural Flint River Basin as a result of incomplete mixing at the confluence of the Flint and Tennessee Rivers, located 5 miles upstream from the intake, and larger percentages of flow from the Flint River to the regulated Tennessee River. For example, during a storm in April 2000, the Flint River contributed 15 percent of streamflow in the Tennessee River, and concentrations of atrazine exceeded 2 micrograms per liter at the intake, whereas concentrations in the main channel were less than 0.4 micrograms per liter. This demonstrates the need for runoff-related monitoring of drinking-water sources even for large source areas with regulated flow. See water.usgs.gov/owq/dwi
Learning Objectives: At the conclusion of the session, the participant will be able to describe the influence of streamflow on source water quality in Tennessee.
Keywords: Drinking Water Quality, Pesticide Contamination
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: U.S. Geological Survey
I have a significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.
Relationship: Employment